The present invention relates generally to a fan located in a motor vehicle for transferring heat by convection from various components, devices or systems using an air stream produced by the fan.
In a hybrid electric vehicle, or a vehicle whose power source is a fuel cell, or a vehicle having a conventional powertrain, a fan having variable speed and operating efficiency is used to maintain temperature in an acceptable range in various vehicle systems. Each system has a specific temperature range at which the system operates at optimum efficiency. The vehicle systems affected by operation of the fan may include engine coolant, transmission oil, power steering oil, engine oil, electric motor and power electronics coolant, fuel cell stacks, battery thermal systems, engine charge air coolers, and refrigerant or air conditioning.
A need exists for a strategy that addresses the temperature requirements of the systems and controls the fan such that its energy consumption, fan power and fan noise are minimized. Preferably the control strategy will also minimize the combined energy consumption both of the fan and of other devices associated with the vehicle systems, such as a refrigerant compressor.
The control strategy should also minimize noise, vibration and harshness (NVH) of the dynamic systems affected by fan operation.